On Mon, 23 Feb 2004, John Hearns wrote:
> I hesitate a bit to send things seen on Slashdot to the list,
> but this is probably relevant:
>>http://www.flashmobcomputing.org/
>> A Flash Mob computer, unlike an ordinary cluster, is temporary and
>> organized on-the-fly for the purpose of working on a single
>> problem. Flash Mob I is the first of it's kind.
A bit of hype here.
Flash Mob is a fun demo, but not a new system architecture. All of the
software is on a live CD, which Yggdrasil pioneered back in 1993, and
it's far from being the first on-the-fly cluster.
One of first public demo of Scyld Beowulf was temporarily converting the
email-reading machines at the ALS conference into a cluster. We did
that in a few minutes, taking only a few second beyond the amount of
time it took to boot the machines from floppy. Today there is the
opportunity to use PXE boot, which makes configuration even easier.
A key was the innovative approach of making most of the systems
specialized compute slaves, with only the environment needed to support
the fully-cached running application. (Note that NFS root sounds like a
likely alternative, but doesn't scale and has a run-time performance
impact.)
> It might be worth a bit of a debate though.
> Given that this cluster will be composed of differing CPUs,
> and conneced together by 100Mbps links will it really have chance
> of getting into the Top 500?
> The bootable CF they are using is a Knoppix variant.
The differing CPUs and full workstation-oriented distribution will
likely pose more a problem than the switched Fast Ethernet.
Unless they make significant modifications, they will run into the
scalability problem that every full-installation system encounters: at
every timestep a few of the machines will be paging, running cron, or
doing something else that slows the machine. That would be barely
noticed in a workstation environment, but is a major problem with most
cluster jobs.
Still, it sounds like a fun, demystifying demo that introduces people to
scalable computing.
--
Donald Becker becker at scyld.com
Scyld Computing Corporation http://www.scyld.com
914 Bay Ridge Road, Suite 220 Scyld Beowulf cluster systems
Annapolis MD 21403 410-990-9993
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